title: Assessment of the relationship between joint laxity and migration of the hip in children with Down syndrome.
abstract: OBJECTIVE
  The aim of this cross-sectional cohort study is to describe the incidence of joint laxity and the correlation between joint laxity and radiological migration of the hip in children with Down syndrome.
  
  
  METHODS
  Sixty-five children (2-19 years) with Down's syndrome were examined for joint laxity. For each subject, laxity scores for joints were carried out with the Bulbena method. Plane pelvic radiographs were used to determine the migration of the hip, according to Reimer's migration index.
  
  
  RESULTS
  In this study, 26 out of 65 children with Down's syndrome (40 %) were diagnosed with general joint laxity. On the radiographs of the hips we found a mean Reimer's Migration Index of 5.2 % for all the subjects. Children with general joint laxity showed a lower Reimer's Migration Index (2.1 %). No significant correlation was found between general joint laxity and migration of the hip.
  
  
  CONCLUSIONS
  This study showed no relationship between joint laxity and migration of the hip in children with Down's syndrome. This implicates that we were not able to prove that joint laxity is the major factor in developing hip migration in children with Down's syndrome.
authors.affiliation: Department of Orthopaedic Surgery, Diakonessenhuis Utrecht, Zeist, The Netherlands.
authors.forename: R
authors.initials: R
authors.lastname: Eshuis
authors.forename: M
authors.initials: M
authors.lastname: Boonzaaijer
authors.forename: H
authors.initials: H
authors.lastname: van Wieringen
authors.forename: J E H
authors.initials: JE
authors.lastname: Pruijs
authors.forename: R J B
authors.initials: RJ
authors.lastname: Sakkers
keywords: Children; Down’s syndrome; Hip dysplasia; Joint laxity; Migration of the hip